EP2288671B1 - Novel transition metal complex and use thereof in organic light-emitting diodes - iii - Google Patents

Abstract

Metal complexes comprising at least one polycyclic aromatic ligand bound to the central metal by way of two nitrogen atoms, an organic light-emitting diode comprising at least one metal complex according to the invention, a light-emitting layer comprising at least one metal complex according to the invention, an organic light-emitting diode comprising at least one light-emitting layer according to the invention, use of the at least one metal complex according to the invention in organic light-emitting diodes and a device selected from the group consisting of stationary screens, such as computer or television screens, screens in printers, cooking devices and billboards, lighting, information boards and mobile screens such as screens in cell phones, laptops, digital cameras, vehicles and destination displays on busses, trains and trams, said device comprising at least one organic light-emitting diode according to the invention.

Description

The present invention relates to metal complexes comprising at least one polycyclic aromatic ligand which is linked to the central metal via two nitrogen atoms, an organic light-emitting diode comprising at least one metal complex according to the invention, a light-emitting layer comprising at least one metal complex according to the invention, an organic light-emitting diode containing at least one light according to the invention layer, the use of the at least one metal complex according to the invention in organic light-emitting diodes and a device selected from the group consisting of stationary screens, such as screens of computers, televisions, screens in printers, kitchen appliances and billboards, lighting, information boards and mobile screens, such as screens in mobile phones, laptops, digital cameras, vehicles and destination displays on buses and trains, containing at least one organic light-emitting diode according to the invention.

In organic light emitting diodes (OLEDs), the property of materials is used to emit light when excited by electric current. OLEDs are of particular interest as an alternative to cathode ray tubes and liquid crystal displays for the production of flat panel displays. Due to the very compact design and the intrinsically low power consumption, the devices containing OLEDs are particularly suitable for mobile applications, eg. For applications such as cell phones, laptops, etc.

The basic principles of the operation of OLEDs and suitable structures (layers) of OLEDs are z. In WO 2005/113704 and their cited literature called.

As light-emitting materials (emitters), phosphorescent materials (phosphorescence emitters) can be used in addition to fluorescent materials (fluorescence emitters). The phosphorescence emitters are usually organometallic complexes which, in contrast to the fluorescence emitters which exhibit a singlet emission, exhibit triplet emission ( MA Baldo et al., Appl. Phys. Lett. 1999, 75, 4 - 6 ). For quantum mechanical reasons, up to fourfold quantum, energy and power efficiency is possible when using the phosphorescence emitter. In order to put into practice the advantages of incorporation of the organometallic phosphorescence emitters, it is necessary to provide phosphorescence emitters having a high operational life, high efficiency, high stability against temperature stress, and a low feed and operating voltage.

To meet the above requirements, numerous phosphorescent emitters have been proposed in the prior art.

So concerns WO 2007/095118 Metal complexes of cyclometallated imidazo [1,2-f] phenanthridine and diimidazo [1,2-A: 1 ', 2'-C] quinazoline ligands and isoelectronic and benzanellated derivatives thereof. The metal complexes according to WO 2007/095118 are characterized in that the abovementioned ligands according to the disclosure in WO 2007/095118 contain as heteroatoms substantially exclusively nitrogen atoms. The metal complexes are phosphorescent and are used in OLEDs. The OLEDs show according to WO 2007/095118 a long lasting and efficient blue, green and red emission.

Object of the present invention over the above-mentioned prior art is to provide further suitable for phosphorescence metal complexes for use in OLEDs that show a balanced range of properties, eg. As good efficiencies, improved lifetime and higher stabilities in the device and good charge transport properties and thermal stability, and the emission in the visible region of the electromagnetic spectrum, preferably in the blue to light blue range of the electromagnetic spectrum, when used in an OLED as emitter electroluminescence show.

worin die Symbole die folgenden Bedeutungen aufweisen:

Y⁵, Z⁴

unabhängig voneinander CR¹, CH oder N;

X², X³, Y², Y³

unabhängig voneinander N oder C;

X⁴, X⁵

unabhängig voneinander CR¹, CH oder N;

Y⁴, Y⁶

unabhängig voneinander CR¹, CH oder N wobei Y⁴ oder Y⁶ im Falle von m = 0 des Weiteren NR², S oder O bedeuten können;

Z¹ Z², Z³

unabhängig voneinander CR¹, CH oder N; wobei Z¹, Z² oder Z³ im Falle von n = 0 des Weiteren NR², S oder O bedeuten können;

R¹

unabhängig voneinander unsubstituiertes oder substituiertes Alkyl, unsubstituiertes oder substituiertes Cycloalkyl, unsubstituiertes oder substituiertesHeterocycloalkyl, unsubstituiertes oder substituiertes Aryl, unsubstituiertes oder substituiertes Heteroaryl, unsubstituiertes oder substituiertes Alkenyl, unsubstituiertes oder substituiertes Cycloalkenyl, unsubstituiertes oder substituiertes Alkinyl, SiR³ ₃, Halogen, ein Substituent mit Donor- oder Akzeptorwirkung; des Weiteren können zwei Reste R¹ gemeinsam eine Alkylen- oder Arylenbrücke bilden;

R²

unabhängig voneinander unsubstituiertes oder substituiertes Alkyl, unsubstituiertes oder substituiertes Aryl oder unsubstituiertes oder substituiertes Heteroaryl; des Weiteren können zwei Reste R² oder ein Rest R² und ein Rest R¹ gemeinsam eine Alkylen- oder Arylenbrücke bilden;

R³

unabhängig voneinander unsubstituiertes oder substituiertes Alkyl, unsubstituiertes oder substituiertes Aryl oder unsubstituiertes oder substituiertes Heteroaryl;

m

0 oder 1, wobei die Gruppen Y⁵ bei m = 0 nicht vorhanden ist;

n

0 oder 1, wobei die Gruppen Z⁴ bei n = 0 nicht vorhanden ist.

This object is achieved by a metal complex containing at least one ligand of the general formula (I)

wherein the symbols have the following meanings:

Y ⁵ , Z ⁴

independently of one another CR ¹ , CH or N;

X ² , X ³ , Y ² , Y ³

independently of one another N or C;

X ⁴ , X ⁵

independently of one another CR ¹ , CH or N;

Y ⁴ , Y ⁶

independently of one another CR ¹ , CH or N, where Y ⁴ or Y ⁶ in the case of m = 0 can furthermore denote NR ² , S or O;

Z ¹ Z ² , Z ³

independently of one another CR ¹ , CH or N; where Z ¹ , Z ² or Z ^{3 may} furthermore denote NR ² , S or O in the case of n = 0;

R ¹

independently of one another unsubstituted or substituted alkyl, unsubstituted or substituted cycloalkyl, unsubstituted or substituted heterocycloalkyl, unsubstituted or substituted aryl, unsubstituted or substituted heteroaryl, unsubstituted or substituted alkenyl, unsubstituted or substituted cycloalkenyl, unsubstituted or substituted alkynyl, SiR ³ ₃ , halogen, a substituent Donor or acceptor action; furthermore, two radicals R ^{1 may} together form an alkylene or arylene bridge;

R ²

independently of one another unsubstituted or substituted alkyl, unsubstituted or substituted aryl or unsubstituted or substituted heteroaryl; furthermore, two radicals R ² or one radical R ² and one radical R ^{1 may} together form an alkylene or arylene bridge;

R ³

independently of one another unsubstituted or substituted alkyl, unsubstituted or substituted aryl or unsubstituted or substituted heteroaryl;

m

0 or 1, where the groups Y ⁵ are absent at m = 0;

n

0 or 1, where the groups Z ⁴ are absent at n = 0.

It has been found that suitable metal complexes can be provided for use in OLEDs, the OLEDs being characterized by a balanced range of properties, e.g. characterized by good efficiencies, excellent durability and very good stabilities in the device as well as good charge transport properties and thermal stability over OLEDs known in the art. When using the metal complexes according to the invention, it is possible to provide OLEDs which emit light in the visible region of the electromagnetic spectrum, in particular the blue to light blue region of the electromagnetic spectrum.

The metal complexes of the invention can be used in any layer of an OLED, wherein the ligand skeleton or central metal for adaptation to desired Properties of the metal complexes can be varied. For example, the use of the metal complexes of the invention in the light-emitting layer, a block layer for electrons, a block layer for excitons, a block layer for holes, a hole transport layer and / or an electron transport layer of the OLED depending on the substitution pattern of the metal complexes of the invention and the electronic conditions possible in further layers present in the OLED. The metal complexes according to the invention are preferably used in the light-emitting layer. Therein, the metal complexes according to the invention can be used as emitter materials and / or matrix materials. The metal complexes of the invention are preferably used as emitter materials in OLEDs.

For the purposes of the present application, the terms unsubstituted or substituted aryl radical or group, unsubstituted or substituted heteroaryl radical or group, unsubstituted or substituted alkyl radical or group, unsubstituted or substituted cycloalkyl radical or group, unsubstituted or substituted heterocycloalkyl radical or group, unsubstituted or substituted alkenyl radical or group, unsubstituted or substituted alkynyl radical or group, aralkyl radical or group, and groups with donor and / or acceptor action have the following meanings:

By an aryl radical (or group) is meant a radical having a skeleton of 6 to 30 carbon atoms, preferably 6 to 18 carbon atoms, which is composed of one aromatic ring or more condensed aromatic rings. Suitable backbones are, for example, phenyl, naphthyl, anthracenyl or phenanthrenyl. This backbone may be unsubstituted (ie, all carbon atoms which are substitutable bear hydrogen atoms) or substituted at one, several or all substitutable positions of the backbone. Suitable substituents are, for example, alkyl radicals, preferably alkyl radicals having 1 to 8 carbon atoms, particularly preferably methyl, ethyl or i-propyl, aryl radicals, preferably C ₆ -aryl radicals, which in turn may be substituted or unsubstituted, heteroaryl radicals, preferably heteroaryl radicals which contain at least one nitrogen atom particularly preferably pyridyl radicals, alkenyl radicals, preferably alkenyl radicals which carry a double bond, particularly preferably alkenyl radicals having a double bond and 1 to 8 carbon atoms, or groups having donor or acceptor action. Suitable groups with donor or acceptor action are mentioned below. Most preferably, the substituted aryl radicals carry substituents selected from the group consisting of methyl, isopropyl, F, CN, aryloxy and alkoxy, thioaryl, thioalkyl, heteroaryl. The aryl radical or the aryl group is preferably a C ₆ -C ₁₈ -aryl radical, particularly preferably a C ₆ -aryl radical which is optionally substituted by at least one or more of the abovementioned substituents. Particularly preferably, the C ₆ -C ₁₈ -aryl radical, preferably C ₆ -aryl, none, one, two, three or four of the abovementioned substituents.

A heteroaryl radical or a heteroaryl radical is to be understood as meaning radicals which differ from the abovementioned aryl radicals in that at least one carbon atom in the skeleton of the aryl radicals is replaced by a heteroatom. Preferred heteroatoms are N, O and S. Most preferably, one or two carbon atoms of the backbone of the aryl radicals are replaced by heteroatoms. Most preferably, the backbone is selected from systems such as pyridine and five-membered heteroaromatics such as pyrrole, furan, pyrazole, imidazole, thiophene, oxazole, thiazole, triazole. The backbone may be substituted at one, several or all substitutable positions of the backbone. Suitable substituents are the same as those already mentioned with respect to the aryl groups.

An alkyl radical or an alkyl group is to be understood as meaning a radical having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, particularly preferably 1 to 8, very particularly preferably 1 to 4 carbon atoms. This alkyl radical may be branched or unbranched and may optionally be interrupted by one or more heteroatoms, preferably Si, N, O or S, more preferably N, O or S. In addition, this alkyl radical may be substituted by one or more of the substituents mentioned with respect to the aryl groups. It is also possible for the alkyl radical to carry one or more (hetero) -aryl groups. For the purposes of the present application, e.g. Benzyl radicals thus substituted alkyl radicals. In this case, all of the above (hetero) aryl groups are suitable. The alkyl radicals are particularly preferably selected from the group consisting of methyl, ethyl, isopropyl, n-propyl, n-butyl, isobutyl and tert-butyl, very particularly preferably methyl, isopropyl.

A cycloalkyl radical or a cycloalkyl radical is to be understood as meaning a radical having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms, particularly preferably 3 to 8 carbon atoms. This backbone may be unsubstituted (i.e., all carbon atoms that are substitutable bear hydrogen atoms) or substituted at one, several, or all substitutable positions of the backbone. Suitable substituents are the groups already mentioned above with respect to the aryl radicals. Examples of suitable cycloalkyl radicals are cyclopropyl, cyclopentyl and cyclohexyl.

A heterocycloalkyl radical or a heterocycloalkyl radical is to be understood as meaning radicals which differ from the above-mentioned cycloalkyl radicals in that in the skeleton of the cycloalkyl radicals at least one carbon atom is replaced by a heteroatom. Preferred heteroatoms are N, O and S. Very particularly preferred are one or two carbon atoms of the backbone of the cycloalkyl radicals replaced by heteroatoms. Examples of suitable heterocycloalkyl radicals are radicals derived from pyrrolidine, piperidine, piperazine, tetrahydrofuran, dioxane.

An alkenyl radical or an alkenyl group is to be understood as meaning a radical which corresponds to the abovementioned alkyl radicals having at least two carbon atoms, with the difference that at least one C-C single bond of the alkyl radical is replaced by a C-C double bond. The alkenyl radical preferably has one or two double bonds.

An alkynyl radical or an alkynyl radical is to be understood as meaning a radical which corresponds to the abovementioned alkyl radicals having at least two carbon atoms, with the difference that at least one C-C single bond of the alkyl radical has been replaced by a C-C triple bond. The alkynyl radical preferably has one or two triple bonds.

The terms alkylene and arylene in the context of the present application have the meanings mentioned with regard to the alkyl and aryl radicals with the difference that the alkylene and arylene groups have two bonding sites.

Preferred alkylene groups are (CR ⁴ ₂ ) _n , where R ^{4 is} H or alkyl, preferably H, methyl or ethyl, particularly preferably H and n is 1 to 3, preferably 1 or 2, particularly preferably 1. Most preferably, the alkylene group is CH ₂ .

Preferred arylene groups are 1,2-, 1,3- or 1,4-phenylene groups which are unsubstituted or which may bear substituents with respect to the aryl radicals.

For the purposes of the present application, a group or a substituent with donor or acceptor action is to be understood as meaning the following groups:

Donor-action groups are to be understood as meaning groups having a + / - and / or + M effect, and groups having an acceptor effect are to be understood as meaning groups having a - | and / or M effect. Suitable groups with donor or acceptor action are halo radicals, preferably F, Cl, Br, particularly preferably F, alkoxy radicals or aryloxy radicals, OR ³ , carbonyl radicals, ester radicals, both oxycarbonyl and carbonyloxy, amino groups, NR ³ ₂ , amide radicals, CH ₂ F Groups, CHF ₂ groups, CF ₃ groups, CN groups, thio groups, sulfonic acid groups, sulfonic acid ester groups, boronic acid groups, boronic acid ester groups, phosphonic acid groups, phosphonic acid ester groups, phosphine radicals, sulfoxide radicals, sulfonyl radicals, sulfide radicals, SR ³ , nitro groups, OCN, borane radicals, silyl groups, SiR ₃ ³ , stannate, imino, hydrazine, hydrazone, oxime, nitroso, diazo, phosphine, hydroxy or SCN groups. Very particularly preferred are F, Cl, CN, aryloxy, alkoxy, amino, CF ₃ groups, sulfonyl, silyl, sulfide and heteroaryl. Especially preferred are heteroaryl, silyl (SiR ³ ₃ ), F, alkoxy or Aryloxy (OR ³ ), sulfide (SR ³ ), amino (NR ³ ₂ ) and CN. The radicals R ³ are defined below.

The aforementioned donor or acceptor groups do not exclude that other of the radicals and substituents recited in the present application which are not listed in the above list of donor or acceptor groups have a donor or acceptor activity.

The aryl radicals or groups, heteroaryl radicals or groups, alkyl radicals or groups, cycloalkyl radicals or groups, heterocycloalkyl radicals or groups, alkenyl radicals or groups, alkynyl radicals or groups and groups having donor and / or acceptor action, and the alkylene and Arylene radicals or groups may be substituted or unsubstituted as mentioned above. For the purposes of the present application, an unsubstituted group is to be understood as meaning a group in which the substitutable atoms of the group carry hydrogen atoms. For the purposes of the present application, a substituted group is to be understood as meaning a group in which one or more substitutable atoms carry a substituent at least at one position instead of one hydrogen atom. Suitable substituents are the substituents mentioned above with respect to the aryl radicals or groups.

If radicals with the same numbering occur several times in the compounds according to the present application, these radicals can each independently have the meanings mentioned.

In one embodiment of the present invention, m and n in the ligands of the general formula (I) can independently of one another denote 0 or 1, the groups Z ⁴ or Y ⁵ not being present at n or m = 0. In the case of m = 0, the aromatic 5-membered ring formed from the elements N, X ² , X ³ , X ⁴ and X ^{5 is} thus formed with one of the elements N, Y ² , Y ³ , Y ⁴ and Y ⁶ 5-ring connected. For m = 1 formed from N, X ^2, X ^3, X ⁴ and X ⁵ aromatic 5-membered ring with one of the elements N, Y ^2, Y ^3, Y ^4, Y ⁵ and Y ⁶ aromatic 6- formed Ring connected. For n = 0 the formed from N, X ^2, X ^3, X ^4, X ⁵ aromatic 5-membered ring is connected to a carrier formed from Z ^1, Z ^2, Z ³ and two carbon atoms aromatic 5-membered ring and for n = 1 For example, the aromatic 5-membered ring formed by N, X ² , X ³ , X ⁴ and X ^{5 is} linked to an aromatic 6-membered ring formed by Z ¹ , Z ² , Z ³ , Z ⁴ and two carbon atoms. Preferably m in the ligands of the formula (I) is 1. In a further preferred embodiment, n = 1. Particularly preferred are both n and m = 1.

• Für m = 1 und n = 0 oder 1 bedeuten :

  X⁴, X⁵, Y⁴, Y⁵, Y⁶, Z¹, Z², Z³, Z⁴

  unabhängig voneinander CR¹, CH oder N;

  X³, Y³

  N oder C, bevorzugt C;

  X², Y²

  N oder C, bevorzugt C;

The symbols X ² , X ³ , X ⁴ , X ⁵ , Y ² , Y ³ , Y ⁴ , Y ⁵ , Y ⁶ , Z ¹ , Z ² , Z ³ , Z ⁴ independently of one another have the following meanings:

• For m = 1 and n = 0 or 1 mean:

  X ⁴ , X ⁵ , Y ⁴ , Y ⁵ , Y ⁶ , Z ¹ , Z ² , Z ³ , Z ⁴

  independently of one another CR ¹ , CH or N;

  X ³ , Y ³

  N or C, preferably C;

  X ² , Y ²

  N or C, preferably C;

Z¹, Z², Z³, Z⁴

unabhängig voneinander CR¹, CH oder N bedeuten, wobei bevorzugt 0, 1 oder 2 Gruppen Z¹, Z², Z³, Z⁴ N bedeuten.

In a further preferred embodiment, the symbols Z ¹ , Z ² , Z ³ , Z ⁴ in the ligand of the formula (I) independently of one another have the following meanings:

Z ¹ , Z ² , Z ³ , Z ⁴

independently of one another are CR ¹ , CH or N, preferably 0, 1 or 2 groups Z ¹ , Z ² , Z ³ , Z ⁴ N.

Y⁴, Y⁵, Y⁶

unabhängig voneinander CH oder CR¹; und

Y², Y³

C.

In a further preferred embodiment, Y ² , Y ³ , Y ⁴ , Y ⁵ and Y ⁶ in the ligand of the formula (I):

Y ⁴ , Y ⁵ , Y ⁶

independently CH or CR ¹ ; and

Y ² , Y ³

C.

X², X³

C; und

X⁴, X⁵

unabhängig voneinander N, CH oder CR¹.

In a further preferred embodiment, X ² , X ³ , X ⁴ and X ⁵ in the ligand of the formula (I):

X ² , X ³

C; and

X ⁴ , X ⁵

independently of one another N, CH or CR ¹ .

In a further embodiment, the skeleton of the ligand of the formula (I) contains, in addition to the two N atoms 0, 1, 2, 3 or 4, preferably 0, 1 or 2 further heteroatoms selected from N, O or S, preferably N. Unter The skeleton of the ligand of the formula (I) is to be understood as meaning the skeleton without consideration of the ligands (radicals R ¹ , R ² , R ³ ) on the skeleton of the formula (I).

worin

R⁴

unabhängig voneinander unsubstituiertes oder substituiertes Alkyl, unsubstituiertes oder substituiertes Aryl, unsubstituiertes oder substituiertes Herteroaryl oder SiR³ ₃ bedeutet, bevorzugt Wasserstoff, Deuterium, Methyl, Ethyl, n-Propyl, isoPropyl, n-Butyl, sec-Butyl, iso-Butyl oder tert-Butyl; unsubstituiertes oder substituiertes C₆-Aryl oder C₅- oder C₆-Heteroaryl, besonders bevorzugt Wasserstoff; und

z

0, 1, 2, 3 oder 4, bevorzugt 0, 1 oder zwei;

bedeuten.R ¹ in the ligand of general formula (I) is independently unsubstituted or substituted alkyl, unsubstituted or substituted cycloalkyl, unsubstituted or substituted heterocycloalkyl, unsubstituted or substituted aryl, unsubstituted or substituted heteroaryl, unsubstituted or substituted alkenyl, unsubstituted or substituted cycloalkenyl, unsubstituted or substituted alkynyl, SiR ³ ₃ , halogen, a substituent with donor or acceptor effect, or two radicals R ¹ may together form an optionally substituted alkylene or arylene bridge. The two radicals R ^{1 may} belong to a single cycle of the ligands of the general formula (I) or to two different cycles of the ligand of the general formula (I). For example, in the case where X ⁴ and X ^{5 are} CR ¹ , the two radicals R ^{1 may} together form an alkylene or arylene bridge. It is also possible that in the case when Z ¹ and X ⁴ or Z ⁴ (at n = 1) or Z ³ (at n = 0) and Y ⁴ CR ¹ , two radicals R ¹ together represent an alkylene or arylene bridge form. Suitable and preferred alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, alkenyl, cycloalkenyl, alkynyl groups and donor or acceptor substituents and alkylene and arylene groups are the groups mentioned above. R ^{1 is} independently of one another unsubstituted or substituted alkyl, unsubstituted or substituted aryl, unsubstituted or substituted heteroaryl, SiR ³ ₃ , halogen, preferably F, OR ³ , SR ³ , NR ³ ₂ , CF ₃ or CN. Most preferably, R ^{1 is} independently unsubstituted or substituted alkyl, unsubstituted or substituted aryl, unsubstituted or substituted heteroaryl or SiR ₃ ^third Most preferably, R ^{1 is} methyl, iso-propyl and tert-butyl; unsubstituted or substituted C ₆ -aryl, suitable substituents being in particular methyl or isopropyl, ortho-disubstituted C ₆ -aryls being particularly preferred; or C ₅ or C ₆ heteroaryl, e.g. B.

wherein

R ⁴

independently of one another are unsubstituted or substituted alkyl, unsubstituted or substituted aryl, unsubstituted or substituted heteroaryl or SiR ³ ₃ , preferably hydrogen, deuterium, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, iso-butyl or tert-butyl; unsubstituted or substituted C ₆ -aryl or C ₅ - or C ₆ -heteroaryl, particularly preferably hydrogen; and

z

0, 1, 2, 3 or 4, preferably 0, 1 or two;

mean.

R ² independently represents unsubstituted or substituted alkyl, unsubstituted or substituted aryl or unsubstituted or substituted heteroaryl, or two radicals R ² or one radical R ² and one radical R ¹ may together form an optionally substituted alkylene or arylene bridge. The two radicals R ² or R ¹ and R ^{2 may} belong to a single cycle of the ligands of the general formula (I) or to two different cycles of the ligand of the general formula (I); suitable and preferred alkyl, aryl and heteroaryl radicals, suitable alkylene or arylene bridges and suitable substituents are mentioned above. R ² is preferably methyl, ethyl, isopropyl, n-propyl, n-butyl, isobutyl, sec-butyl or tert-butyl or C ₆ -aryl, which may be unsubstituted or substituted, preferably phenyl or ortho, ortho-dialkyl-substituted phenyl.

R ³ is independently unsubstituted or substituted alkyl, unsubstituted or substituted aryl or unsubstituted or substituted heteroaryl with suitable and preferred alkyl, aryl and heteroaryl radicals and suitable substituents mentioned above. R ³ is preferably methyl, ethyl, isopropyl, n-propyl, n-butyl, isobutyl, sec-butyl or tert-butyl or C ₆ -aryl, which may be unsubstituted or substituted, preferably phenyl or tolyl.

The metal complex of the invention preferably contains a metal atom selected from the group consisting of transition metals of group IB, IIB, IIIB, IVB, VB, VIB, VIIB, VIII of the Periodic Table of the Elements (CAS version), in each possible oxidation state for the corresponding metal atom. The metal complexes according to the invention preferably contain a metal atom M selected from the group consisting of Ir, Co, Rh, Ni, Pd, Pt, Fe, Ru, Os, Cr, Mo, W, Mn, Tc, Re, Ag, Au and Cu and more preferably Ir, Os, Ru, Rh, Pd, Co, Ni and Pt, most preferably Ir, Pt, Rh, Ru and Os in any oxidation state possible for the corresponding metal atom. Particularly preferred are Pt (II), Pt (IV), Ir (I), Ir (III), Os (II) and Ru (II), more preferably Pt (II), Ir (III) and Os (II) and most preferably Ir (III) is used.

In addition to the at least one ligand of the general formulas (I), the metal complex according to the invention may contain other ligands other than the ligands of the general formula (I). For example, in addition to at least one ligand of the general formula (I) one or more neutral mono- or bidentate Ligands K and optionally one or more mono- or dianionic ligands J, which may be mono- or bidentate, are present. Furthermore, different ligands of the formula (I) can be present in the metal complex according to the invention. A bidentate ligand is to be understood as meaning a ligand which is coordinated to the metal atom M at two points. For the purposes of the present application, the term "bidentate" is used synonymously with the term "bidentate".

A monodentate ligand is to be understood as meaning a ligand which coordinates with the metal atom M at one point of the ligand.

worin bedeuten:

M

Metallatom ausgewählt aus der Gruppe bestehend aus Übergangsmetallen der Gruppe IB, IIB, IIIB, IVB, VB, VIB, VIIB, VIII des Periodensystems der Elemente (CAS-Version), in jeder für das entsprechende Metallatom möglichen Oxidationsstufe; bevorzugt Ir(III), Pt(II) oder Os(II), besonders bevorzugt Ir(III);

J

mono- oder dianionischer Ligand, der mono- oder bidentat sein kann, bevorzugt bidentater, monoanionischer Ligand;

K

neutraler, mono- oder bidentater Ligand, der im Allgemeinen nicht photoaktiv ist: bevorzugte Liganden K sind Phosphine, insbesondere Trialkylphosphine, z. B. PEt₃, PnBu₃, Triarylphosphine, z. B. PPh₃; Phosphonate und Derivate davon, Arsenate und Derivate davon, Phosphite, CO, Nitrile, Amine, Diene, die einen π-Komplex mit M bilden können, z. B. 2,4-Hexadien, η⁴-Cyclooctadien und η²-Cyclooctadien (jeweils 1,3 und 1,5), Allyl, Methallyl, Cycloocten, Norbornadien und neutralen Biscarbene, z.B. die in WO 2008/000726 offenbarten neutralen Biscarbene;

o

1, 2, 3 oder 4; wobei o bevorzugt für M = Ir(III) 1, 2 oder 3, besonders bevorzugt 2 oder 3 und für M = Pt(II) oder Os(II) 1 oder 2 bedeutet;

p

0, 1, 2, 3 oder 4; wobei p bevorzugt für M = Ir(III) 0, 1 2, 3 oder 4, besonders bevorzugt 0 oder 2 und für M = Pt(II) und Os(II) 0, 1 oder 2, besonders bevorzugt 0 oder 2 für M = Pt(II) und besonders bevorzugt 0 für M = Os(II) bedeutet, wobei p die Zahl der Bindungsstellen zum Metall M bedeutet, d.h., wenn p = 2 ist, kann es sich um zwei monodentate oder einen bidentaten Liganden handeln;

q

0, 1, 2, 3 oder 4; wobei q bevorzugt für M = Ir(III) 0, 1 oder 2, besonders bevorzugt 0; für M = Pt(II) 0 oder 1, besonders bevorzugt 0, und für Os(II) 2 oder 3, besonders bevorzugt 2, bedeutet, wobei q die Zahl der Bindungsstellen zum Metall M bedeutet, d.h., wenn q = 2 ist, kann es sich um zwei monodentate oder einen bidentaten Liganden handeln;

wobei o, p und q von der Oxidationsstufe und Koordinationszahl des eingesetzten Metallatoms und der Ladung der Liganden abhängig sind.Thus, in a preferred embodiment, the present invention relates to metal complexes of the general formula (II)

in which mean:

M

Metal atom selected from the group consisting of transition metals of group IB, IIB, IIIB, IVB, VB, VIB, VIIB, VIII of the Periodic Table of the Elements (CAS version), in each possible oxidation state for the corresponding metal atom; preferably Ir (III), Pt (II) or Os (II), more preferably Ir (III);

J

mono- or dianionic ligand, which may be mono- or bidentate, preferably bidentate, monoanionic ligand;

K

neutral, mono- or bidentate ligand which is generally non-photoactive: preferred K ligands are phosphines, especially trialkyl phosphines, e.g. PEt ₃ , PnBu ₃ , triarylphosphines, e.g. B. PPh ₃ ; Phosphonates and derivatives thereof, arsenates and derivatives thereof, phosphites, CO, nitriles, amines, dienes which can form a π-complex with M, e.g. B. 2,4-hexadiene, η ⁴ -cyclooctadiene and η ² -cyclooctadiene (each 1.3 and 1.5), allyl, methallyl, cyclooctene, norbornadiene and neutral biscarbenes, eg those in WO 2008/000726 disclosed neutral biscarbenes;

O

1, 2, 3 or 4; wherein o is preferably for M = Ir (III) 1, 2 or 3, particularly preferably 2 or 3 and for M = Pt (II) or Os (II) 1 or 2;

p

0, 1, 2, 3 or 4; where p is preferably for M = Ir (III) 0, 1 2, 3 or 4, particularly preferably 0 or 2 and for M = Pt (II) and Os (II) 0, 1 or 2, particularly preferably 0 or 2 for M = Pt (II) and more preferably 0 for M = Os (II), where p is the number of bonding sites to the metal M, ie, when p = 2, may be two monodentate or one bidentate ligand;

q

0, 1, 2, 3 or 4; where q is preferably for M = Ir (III) 0, 1 or 2, particularly preferably 0; for M = Pt (II) 0 or 1, more preferably 0, and for Os (II) 2 or 3, more preferably 2, where q is the number of bonding sites to the metal M, ie, if q = 2, it may be two monodentates or one bidentate ligand;

where o, p and q are dependent on the oxidation state and coordination number of the metal atom used and the charge of the ligands.

In the event that the number o, p or q is> 1, the ligands of the formula (I), K or J employed can each be identical or different.

For M = Ir (III), the sum o, p + q in the metal complex of the formula (II) according to the invention is generally 3 or 4 or 5, i. in the case when 3 ligands of formula (I) are present, o is 3 and when 2 ligands of formula (I) and e.g. 1 bidentate, monoanionic ligand J is o 2 and p 2, and in the case when z. B. 2 ligands of the formula (I), 1 bidentater, monoanionic ligand J and 1 neutral monoanionic ligand K, is o 2, p 2 and q 1. For M = Pt (II) is the sum o + p in the inventive Metal complex of the formula (II) in general 2 or 3, ie in the case when 2 ligands of formula (I) are present, o is 2 and when 1 ligand of formula (I) and e.g. 1 bidentater, monoanionic ligand J is present, o is 1 and p 2, where o is at least 1 in each case. For Os (II), the sum o, p + q in the metal complex of the formula (II) according to the invention is generally 4 or 5, i. when 2 ligands of formula (I) and e.g. 1 bidentater, neutral ligand K is present, o 2 and q 2, and in the case when z. B. 1 ligand of the formula (I), 1 bidentater, monoanionic ligand J and 1 neutral bidentate ligand K are present, o is 1, p 2 and q.

The symbols X ² , X ³ , X ⁴ , X ⁵ , Y ² , Y ³ , Y ⁴ , Y ⁵ , Y ⁶ , Z ¹ , Z ² , Z ³ , Z ⁴ , m and n in the metal complex of the formula ( II) have the meanings given above.

If different isomers of the metal complexes according to the invention can be present, the present invention comprises both the individual isomers of the metal complexes, as well as mixtures of different isomers in any mixing ratio. In general, various isomers of the metal complexes can be prepared by methods known to those skilled in the art, e.g. Example, by chromatography, sublimation or crystallization, are separated.

, worin L jeweils unabhängig voneinander ausgewählt ist aus O, N und C. Bevorzugt sind bidentate, monoanionische Liganden J, worin beide Gruppen L O, C oder N bedeuten, oder eine Gruppe L O bedeutet und die andere Gruppe L N oder C bedeutet, oder eine Gruppe L C bedeutet und die anderen Gruppe L N bedeutet. Besonders bevorzugte bidentate, monoanionische Liganden sind Acetylacetonat und dessen Derivate, Picolinat und dessen Derivate, bidentate, monoanionische Carbenliganden und dessen Derivate, z.B. Carbenliganden, die in WO 2005/019373 , WO 2005/0113704 , WO 2006/018292 , WO 2006/056418 , WO 2007/115981 , WO 2007/115970 , WO 2008/000727 , WO 2006/067074 , WO 2006/106842 , WO 2007/018067 , WO 2007/058255 , WO 2007/069542 , US 2007/108891 , WO 2007/058080 , WO 2007/058104 genannt sind, sowie die in WO 02/15645 , WO 2005/123873 , US 2007/196690 , WO 2006/121811 genannten bidentaten, monoanionischen Liganden. Besonders bevorzugt sind die bidentaten, monoanionischen Liganden ausgewählt aus der Gruppe bestehend aus Acetylacetonat, Picolinat, Carbenen wie N-Methyl-N-arylimidazolcarben, Arylpyridinen wie 2-Arylpyridinen, insbesondere Phenylpyridinen wie 2-Phenylpyridin, Arylimidazolen wie 2-Arylimidazolen, insbesondere Phenylimidazolen, wie 2-Phenylimidazol und Derivaten der vorstehend genannten Verbindungen.Usually, non-photoactive or photoactive (eg heteroleptic complexes with carbenes, phenylpyridines or phenylimidazoles) ligands are used as bidentate, monoanionic ligands. Suitable ligands J are, for example, bidentate, monoanionic ligands of the general formula

wherein each L is independently selected from O, N and C. Preferred are bidentate, monoanionic ligands J wherein both groups are LO, C or N, or one group is LO and the other group is LN or C, or a group LC means and the other group means LN. Particularly preferred bidentate, monoanionic ligands are acetylacetonate and its derivatives, picolinate and its derivatives, bidentate, monoanionic carbene ligands and its derivatives, eg carbene ligands, which are disclosed in US Pat WO 2005/019373 . WO 2005/0113704 . WO 2006/018292 . WO 2006/056418 . WO 2007/115981 . WO 2007/115970 . WO 2008/000727 . WO 2006/067074 . WO 2006/106842 . WO 2007/018067 . WO 2007/058255 . WO 2007/069542 . US 2007/108891 . WO 2007/058080 . WO 2007/058104 are called, as well as in WO 02/15645 . WO 2005/123873 . US 2007/196690 . WO 2006/121811 bidentate, monoanionic ligands. Particularly preferred are the bidentate, monoanionic ligands selected from the group consisting of acetylacetonate, picolinate, carbenes such as N-methyl-N-arylimidazolcarben, arylpyridines such as 2-arylpyridines, in particular phenylpyridines such as 2-phenylpyridine, arylimidazoles such as 2-arylimidazoles, in particular phenylimidazoles, such as 2-phenylimidazole and derivatives of the aforementioned compounds.

worin bedeuten

M

Metallatom ausgewählt aus der Gruppe bestehend aus Übergangsmetallen der Gruppe IB, IIB, IIIB, IVB, VB, VIB, VIIB, VIII des Periodensystems der Elemente (CAS-Version), in jeder für das entsprechende Metallatom möglichen Oxidationsstufe; bevorzugt Ir(III) oder Pt(II), besonders bevorzugt Ir(III);

bidentater monoanionischer Ligand;

o

1, 2, 3, 4; wobei o bevorzugt für M = Ir(III) 1, 2 oder 3, besonders bevorzugt 2 oder 3 und für M = Pt(II) 1 oder 2; bedeutet

p'

0, 1 oder 2; wobei p' bevorzugt für M = Ir(III) 0, 1 oder 2, besonders bevorzugt 0 oder 1 und für M = Pt(II) 0 oder 1; bedeutet, wobei p' die Zahl der Liganden

bedeutet;

wobei o und p' von der Oxidationsstufe und Koordinationszahl des eingesetzten Metallatoms abhängig sind.In a particularly preferred embodiment, the metal complex according to the invention has the general formula (IIa).

in which mean

M

Metal atom selected from the group consisting of transition metals of group IB, IIB, IIIB, IVB, VB, VIB, VIIB, VIII of the Periodic Table of the Elements (CAS version), in each possible oxidation state for the corresponding metal atom; preferably Ir (III) or Pt (II), more preferably Ir (III);

bidentate monoanionic ligand;

O

1, 2, 3, 4; where o is preferably for M = Ir (III) 1, 2 or 3, particularly preferably 2 or 3 and for M = Pt (II) 1 or 2; means

p '

0, 1 or 2; where p 'is preferably for M = Ir (III) 0, 1 or 2, particularly preferably 0 or 1 and for M = Pt (II) 0 or 1; where p 'is the number of ligands

means;

where o and p 'are dependent on the oxidation state and coordination number of the metal atom used.

For M = Ir (III), the sum o + p 'in the metal complexes of the formula (IIa) according to the invention is particularly preferably 3, and for M = Pt (II) the sum o + p' is particularly preferably 2, where o is at least 1 is.

The further symbols and indices in the metal complex of the formula (IIa) have the meanings given above. Furthermore, further embodiments of M, the bidentate, monoanionic ligand and of o and p 'are those mentioned above for M, the bidentate, monoanionic ligands, o and p' (or p, where p '= 1 p = 2) embodiments.

worin M, o und p' in Formel (IIaa) unabhängig voneinander die vorstehend genannten Bedeutungen aufweisen; und
in den Verbindungen der Formel IIaa:

X⁴, X⁵

unabhängig voneinander CR¹, CH oder N;

Z¹, Z², Z³, Z⁴

CH oder N; und

bedeuten;
wobei R¹ die vorstehend genannten Bedeutungen aufweist.In a particularly preferred embodiment, the present invention relates to metal complexes of the formula (IIaa)

wherein M, o and p 'in formula (IIaa) independently of one another have the meanings given above; and
in the compounds of formula IIaa:

X ⁴ , X ⁵

independently of one another CR ¹ , CH or N;

Z ¹ , Z ² , Z ³ , Z ⁴

CH or N; and

mean;
wherein R ^{1 has} the meanings given above.

Below, by way of example, preferred metal complexes according to the invention of the formula (IIaa) are listed.

The metal complexes according to the invention can be prepared by processes known to the person skilled in the art or by processes known to those skilled in the art. Suitable manufacturing processes are for. B. analogous to those in the examples of WO 2007/095118 mentioned method.

Usually, the metal complexes according to the invention are prepared starting from the ligand precursors corresponding to the ligands of the general formula (I). The metal complexes according to the invention are prepared by reacting at least one ligand precursor based on the ligands of the general formula (I) with a metal complex containing at least one metal M, where M has the abovementioned meanings.

The molar ratio between the ligand precursors based on the ligands of the formula (I) and the metal complex containing at least one metal M depends on the structure of the desired metal complex according to the invention and on the number of ligands of the formula (I). In the case that o in the inventive Metal complexes> 1, it is possible that these metal complexes are obtained by reacting the metal complex containing at least one metal M with identical ligand precursors or by reacting with different ligand precursors. Suitable methods and reaction sequences for the preparation of the various metal complexes according to the invention are known to the person skilled in the art.

The metal complex to be reacted with the ligand precursor containing at least one metal M is a metal complex containing at least one metal atom selected from the group consisting of transition metals of group IB, IIB, IIIB, IVB, VB, VIB, VIIB, VIII of the Periodic Table of the Elements (CAS version), preferably selected from the group consisting of Ir, Co, Rh, Ni, Pd, Pt, Fe, Ru, Os, Cr, Mo, W, Mn, Tc, Re and Cu, more preferably Ir, Os Ru, Rh, Pd, Co and Pt, most preferably Ir, Pt, Rh, Pd, Ru and Os in any suitable oxidation state possible for the corresponding metal.

Suitable metal complexes to be reacted with the ligand precursor are known to the person skilled in the art. Examples of suitable metal complexes are: Pd (OAc) ₂ , Pt (cod) Cl ₂ , Pt (cod) Me ₂ , Pt (acac) ₂ , Pt (PPh ₃ ) ₂ Cl ₂ , PtCl ₂ , [Rh (cod) Cl ] _2, Rh (acac) CO _(PPh3), Rh (acac) (CO) _2, Rh (cod) ₂ BF _4, RhCl _{(PPh3) 3,} RhCl ₃ x nH ₂ O, Rh (acac) _3, [Os (CO) ₃ I ₂ ] ₂ , [Os ₃ (CO) ₁₂ ], OsH ₄ (PPh ₃ ) ₃ Cp ₂ Os, Cp * ₂ Os, H ₂ OsCl ₆ x 6H ₂ O, OsCl ₃ x H ₂ O, Ru (acac) ₃ , RuCl ₂ (cod), Ru (2-methylallyl) ₂ (cod), [(μ-Cl) Ir (η ⁴ -1,5-cod)] ₂ , [(μ-Cl ) Ir (η ² -coe) ₂ ] ₂ , Ir (acac) ₃ , IrCl ₃ × nH ₂ O, (tht) ₃ IrCl ₃ , Ir (η ³ -allyl) ₃ , Ir (η ³ -metallyl) ₃ , wherein cod is cyclooctadiene, coe cyclooctene, acac acetylacetonate and tht tetrahydrothiophene. The metal complexes can be prepared according to processes known to the person skilled in the art or are commercially available.

Following the abovementioned reaction of the metal complex to be reacted with the ligand precursor with one or more ligand precursors, the resultant metal complex according to the invention is generally worked up by methods known to the person skilled in the art and optionally purified. Usually, work-up and purification by extraction, column chromatography and / or recrystallization are carried out according to methods known to the person skilled in the art.

The metal complexes according to the invention are used in organic light-emitting diodes (OLEDs). They are suitable as emitter substances because they have an emission (electroluminescence) in the visible range of the electromagnetic spectrum. With the aid of the metal complexes according to the invention as emitter substances, it is possible to provide compounds which exhibit electroluminescence, preferably electrophosphorescence, in particular at wavelengths of 450 to 500 nm, of the electromagnetic spectrum with good efficiency. Here is the quantum yield high and especially the lifetime and stability of the metal complexes of the invention in the device high.

Furthermore, the metal complexes according to the invention are suitable as electron, exciton or hole blockers, hole conductors, electron conductors, hole injection layer or matrix material in OLEDs, depending on the ligands used and the central metal used.

1. 1. Anode (1)
2. 2. Löcher-transportierende Schicht (2)
3. 3. Licht-emittierende Schicht (3)
4. 4. Elektronen-transportierende Schicht (4)
5. 5. Kathode (5)

Organic light-emitting diodes (OLEDs) are basically made up of several layers:

1. 1. anode (1)
2. 2. hole-transporting layer (2)
3. 3. Light-emitting layer (3)
4. 4. Electron-transporting layer (4)
5. 5. Cathode (5)

However, it is also possible that the OLED does not have all of the layers mentioned, for example an OLED with the layers (1) (anode), (3) (light-emitting layer) and (5) (cathode) is also suitable. wherein the functions of the layers (2) (hole-transporting layer) and (4) (electron-transporting layer) are taken over by the adjacent layers. OLEDs comprising layers (1), (2), (3) and (5) or layers (1), (3), (4) and (5) are also suitable.

The metal complexes of the invention can be used in different layers of an OLED. Another object of the present invention is therefore an OLED containing at least one metal complex according to the invention and the use of at least one metal complex according to the invention in OLEDs. The metal complexes according to the invention are preferably used in the light-emitting layer, particularly preferably as emitter molecules. Another object of the present invention is therefore a light-emitting layer containing at least one metal complex of the invention as a matrix material or emitter molecule, preferably as an emitter molecule. Preferred metal complexes according to the invention are mentioned above.

The metal complexes according to the invention can be used in bulk - without further additives - in the light-emitting layer or another layer of the OLED, preferably in the light-emitting layer. However, it is also possible and preferred that, in addition to the metal complexes according to the invention, further compounds are present in the layers, preferably in the light-emitting layer. For example, a fluorescent dye may be present in the light-emitting layer in order to change the emission color of the metal complex according to the invention used as an emitter molecule. Furthermore, in a preferred embodiment, at least one matrix material can be used. Suitable matrix materials are known to the person skilled in the art. In general, the matrix material is selected such that the band gap of the matrix material is greater than the band gap of the metal complex according to the invention used as emitter. Under band gap is to be understood in the sense of the present application, the triplet energy. Preferably used suitable matrix materials, in particular when using metal complexes according to the invention as emitter materials which emit light in the blue region of the electromagnetic spectrum, are e.g. B. carbene complexes, in particular those in WO 2005/019373 . WO 2005/0113704 . WO 2006/018292 . WO 2006/056418 . WO 2007/115981 . WO 2008/000726 and WO 2008/000727 Carbene complexes mentioned; Disilylcarbazoles, for example 9- (4-tert-butylphenyl) -3,6-bis (triphenylsilylcarbazole), 9- (phenyl) -3,6-bis (triphenylsilyl) carbazole and in the not prepublished PCT application with the File number PCT / EP 2007/059648 called disilylcarbazoles and the in WO 2004/095889 . EP 1617710 . EP 1617711 . WO 2006/112265 . WO 2006/130598 listed compounds.

The individual of the abovementioned layers of the OLED can in turn be made up of 2 or more layers. For example, the hole-transporting layer may be composed of a layer into which holes are injected from the electrode and a layer that transports the holes away from the hole-injecting layer into the light-emitting layer. The electron-transporting layer may also consist of several layers, for example a layer in which electrons are injected through the electrode and a layer which receives electrons from the electron-injection layer and transports them into the light-emitting layer. These mentioned layers are each selected according to factors such as energy level, temperature resistance and charge carrier mobility, as well as the energy difference of said layers with the organic layers or the metal electrodes. The skilled person is able to choose the structure of the OLEDs so that it is optimally adapted to the metal complexes according to the invention, preferably used as emitter substances.

To obtain particularly efficient OLEDs, the HOMO (highest occupied molecular orbital) of the hole-transporting layer should be aligned with the work function of the anode, and the LUMO (lowest unoccupied molecular orbital) of the electron-transporting layer should be aligned with the work function of the cathode.

A further subject of the present application is an OLED containing at least one light-emitting layer according to the invention. The further layers in the OLED may be constructed of any material commonly employed in such layers and known to those skilled in the art.

Suitable materials for the abovementioned layers (anode, cathode, hole and electron-injection materials, hole and electron transport materials and hole and electron block materials, matrix materials, fluorescence and phosphorescence emitters) are known to the person skilled in the art and are described, for example, in US Pat H. Meng, N. Herron, Organic Small Molecule Materials for Organic Light-Emitting Devices in Organic Light-Emitting Materials and Devices, Ed .: Z. Li, H. Meng, Taylor & Francis, 2007, Chapter 3, pages 295 to 411 called.

The anode (1) is an electrode that provides positive charge carriers. For example, it may be constructed of materials including a metal, a mixture of various metals, a metal alloy, a metal oxide, or a mixture of various metal oxides. Alternatively, the anode may be a conductive polymer. Suitable metals include the metals of Groups 11, 4, 5 and 6 of the Periodic Table of Elements and the transition metals of Groups 8 to 10. When the anode is to be transparent, mixed metal oxides of Groups 12, 13 and 14 of the Periodic Table of the Elements are generally used used, for example indium tin oxide (ITO). It is also possible that the anode (1) contains an organic material, for example polyaniline, such as in Nature, Vol. 357, pages 477 to 479 (June 11, 1992 ) is described. At least either the anode or the cathode should be at least partially transparent in order to be able to decouple the light formed.

Suitable hole transport materials for the layer (2) of the inventive OLEDs are, for example, in Kirk-Othmer Encyclopedia of Chemical Technology, 4th Edition, Vol. 18, pages 837 to 860, 1996 disclosed. Both hole transporting molecules and polymers can be used as hole transport material. Commonly used hole transporting molecules are selected from the group consisting of 4,4'-bis [N- (1-naphthyl) -N-phenyl-amino] biphenyl (α-NPD), N, N'-diphenyl-N, N '- bis (3-methylphenyl) - [1,1'-biphenyl] -4,4'-diam in (T PD), 1,1-bis [(di-4-tolylamino) -phenyl] cyclohexane (TAPC) , N, N'-bis (4-methylphenyl) -N, N'-bis (4-ethylphenyl) - [1,1 '- (3,3'-dimethyl) biphenyl] -4,4'-diamine (ETPD), tetrakis (3-methylphenyl) -N, N, N ', N'-2,5-phenylenediamine (PDA), α-phenyl-4-N, N-diphenylaminostyrene (TPS), p- (diethylamino ) benzaldehyde diphenylhydrazone (DEH), triphenylamine (TPA), bis [4- (N, N-diethylamino) -2-methylphenyl) (4-methylphenyl) methane (MPMP), 1-phenyl-3- [p- ( diethylamino) styryl] -5- [p- (diethylamino) phenyl] pyrazoline (PPR or DEASP), 1,2-trans-bis (9H-carbazol-9-yl) cyclobutane (DCZB), N, N, N ', N'-tetrakis (4-methylphenyl) - (1,1'-biphenyl) -4,4'-diamine (TTB) 4,4 ', 4 "-tris (N, N-diphenylamino) triphenylamine (TDTA) and porphyrin compounds Usually, hole-transporting polymers are selected from the group consisting of polyvinylcarbazoles, (phenylmethyl) polysilanes, PEDOT (poly (3,4-ethylenedioxythiophene), preferably PEDOT doped with PSS (polystyrene sulfonate), and polyanilines.) It is also possible, hole-transporting polymers by doping hole-transporting molecules in polymers such as polystyrene un d to obtain polycarbonate. Suitable hole-transporting molecules are the molecules already mentioned above.

Suitable electron transport materials for the layer (4) of the OLEDs according to the invention comprise chelated metals with oxinoid compounds such as tris (8-hydroxyquinolato) aluminum (Alq ₃ ), phenanthroline-based compounds such as 2,9-dimethyl, 4,7-diphenyl-1, 10 phenanthroline (DDPA = BCP) or 4,7-diphenyl-1,10-phenanthroline (DPA) and azole compounds such as 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole ( PBD) and 3- (4-biphenylyl) -4-phenyl-5- (4-t-butylphenyl) -1,2,4-triazole (TAZ). In this case, the layer (4) can serve both to facilitate the electron transport and as a buffer layer or as a barrier layer in order to avoid quenching of the exciton at the interfaces of the layers of the OLED. Preferably, the layer (4) improves the mobility of the electrons and reduces quenching of the exciton.

Among the materials mentioned above as hole transporting materials and electron transporting materials, some may fulfill several functions. For example, some of the electron-conducting materials are simultaneously hole-blocking materials if they have a deep HOMO.

The charge transport layers can also be electronically doped in order to improve the transport properties of the materials used, on the one hand to make the layer thicknesses more generous (avoidance of pinholes / short circuits) and on the other hand to minimize the operating voltage of the device. For example, the hole transport materials can be doped with electron acceptors, for example phthalocyanines or arylamines such as TPD or TDTA can be doped with tetrafluorotetracyanoquinodimethane (F4-TCNQ). The electron transport materials For example, they may be doped with alkali metals, for example Alq ₃ with lithium. The electronic doping is known in the art and, for example, in W. Gao, A. Kahn, J. Appl. Phys., Vol. 94, no. 1, 1 July 2003 (p-doped organic layers); AG Werner, F. Li, K. Harada, M. Pfeiffer, T. Fritz, K. Leo, Appl. Phys. Lett., Vol. 82, no. 25, 23 June 2003 and Pfeiffer et al., Organic Electronics 2003, 4, 89-103 disclosed.

The cathode (5) is an electrode which serves to introduce electrons or negative charge carriers. The cathode may be any metal or non-metal that has a lower work function than the anode. Suitable materials for the cathode are selected from the group consisting of Group 1 alkali metals, for example Li, Cs, Group 2 alkaline earth metals, Group 12 metals of the Periodic Table of the Elements comprising the rare earth metals and the lanthanides and actinides. Furthermore, metals such as aluminum, indium, calcium, barium, samarium and magnesium and combinations thereof can be used. Furthermore, lithium-containing organometallic compounds or LiF can be applied between the organic layer and the cathode to reduce the operating voltage.

The OLED according to the present invention may additionally contain further layers which are known to the person skilled in the art. For example, a layer can be applied between the layer (2) and the light-emitting layer (3), which facilitates the transport of the positive charge and / or adapts the band gap of the layers to one another. Alternatively, this further layer can serve as a protective layer. In an analogous manner, additional layers may be present between the light-emitting layer (3) and the layer (4) to facilitate the transport of the negative charge and / or to match the band gap between the layers. Alternatively, this layer can serve as a protective layer.

• eine Loch-Injektionsschicht zwischen der Anode (1) und der Löchertransportierenden Schicht (2);
• eine Blockschicht für Elektronen und/oder Excitonen zwischen der Löchertransportierenden Schicht (2) und der Licht-emittierenden Schicht (3);
• eine Blockschicht für Löcher und/oder Excitonen zwischen der Licht-emittierenden Schicht (3) und der Elektronen-transportierenden Schicht (4);
• eine Elektronen-Injektionsschicht zwischen der Elektronen-transportierenden Schicht (4) und der Kathode (5).

In a preferred embodiment, in addition to the layers (1) to (5), the OLED according to the invention contains at least one of the further layers mentioned below:

• a hole injection layer between the anode (1) and the hole-transporting layer (2);
• a blocking layer for electrons and / or excitons between the hole-transporting layer (2) and the light-emitting layer (3);
• a blocking layer for holes and / or excitons between the light-emitting layer (3) and the electron-transporting layer (4);
• an electron injection layer between the electron-transporting layer (4) and the cathode (5).

However, as already mentioned above, it is also possible that the OLED does not have all of the mentioned layers (1) to (5), for example an OLED with the layers (1) (anode), (3) (light-emitting Layer) and (5) (cathode) are also suitable, wherein the functions of the layers (2) (hole-transporting layer) and (4) (electron-transporting layer) are taken over by the adjacent layers. OLEDs comprising layers (1), (2), (3) and (5) or layers (1), (3), (4) and (5) are also suitable.

The person skilled in the art knows how to select suitable materials (for example based on electrochemical investigations). Suitable materials for the individual layers and suitable OLED structures are known in the art and z. In WO2005 / 113704 disclosed.

Furthermore, each of the mentioned layers of the OLED according to the invention can be constructed from two or more layers. Further, it is possible that some or all of the layers (1), (2), (3), (4) and (5) are surface treated to increase the efficiency of charge carrier transport. The selection of materials for each of said layers is preferably determined by obtaining an OLED having a high efficiency.

The preparation of the OLED according to the invention can be carried out by methods known to the person skilled in the art. In general, the OLED is produced by successive vapor deposition of the individual layers onto a suitable substrate. Suitable substrates are, for example, glass or polymer films. For vapor deposition, conventional techniques can be used such as thermal evaporation, chemical vapor deposition and others. In an alternative method, the organic layers may be coated from solutions or dispersions in suitable solvents using coating techniques known to those skilled in the art. Compositions which, in addition to the at least one metal complex according to the invention, comprise a polymeric material in one of the layers of the OLED, preferably in the light-emitting layer, are generally applied as a layer by means of solution-processing methods.

In general, the various layers have the following thicknesses: anode (1) 500 to 5000 Å, preferably 1000 to 2000 Å; Hole-transporting layer (2) 50 to 1000 Å, preferably 200 to 800 Å, light-emitting layer (3) 10 to 1000 Å, preferably 100 to 800 Å, electron transporting layer (4) 50 to 1000 Å, preferably 200 to 800 Å, cathode (5) 200 to 10,000 Å, preferably 300 to 5000 Å. The position of the recombination zone of holes and electrons in the OLED according to the invention and thus the emission spectrum of the OLED can be influenced by the relative thickness of each layer. That is, the thickness of the electron transport layer should preferably be selected so that the electron / holes recombination zone is in the light-emitting layer. The ratio of the layer thicknesses of the individual layers in the OLED depends on the materials used. The layer thicknesses of optionally used additional layers are known to the person skilled in the art.

By using the metal complexes according to the invention in at least one layer of the OLED according to the invention, preferably as emitter molecule in the light-emitting layer of the OLEDs according to the invention, OLEDs can be obtained with high efficiency. The efficiency of the OLEDs according to the invention can be further improved by optimizing the other layers. For example, highly efficient cathodes such as Ca, Ba or LiF can be used. Shaped substrates and new hole-transporting materials that bring about a reduction in the operating voltage or an increase in quantum efficiency are also usable in the OLEDs according to the invention. Furthermore, additional layers may be present in the OLEDs to adjust the energy levels of the various layers and to facilitate electroluminescence.

The OLEDs according to the invention can be used in all devices in which electroluminescence is useful. Suitable devices are preferably selected from stationary and mobile screens. Stationary screens are e.g. Screens of computers, televisions, screens in printers, kitchen appliances and billboards, lights and signboards. Mobile screens are e.g. Screens in mobile phones, laptops, cameras, in particular digital cameras, vehicles and destination displays on buses and trains.

Furthermore, the metal complexes according to the invention can be used in OLEDs with inverse structure. The metal complexes according to the invention are preferably used in these inverse OLEDs again in the light-emitting layer. The construction of inverse OLEDs and the materials usually used therein are known to the person skilled in the art.

Claims (15)

1. A metal complex comprising at least one ligand of the general formula (I)

   

   in which the symbols are each defined as follows:

   Y⁵, Z⁴ are each independently CR¹, CH or N;

   X², X³, Y², Y³ are each independently N or C;

   X⁴, X⁵ are each independently CR¹, CH or N;

   Y⁴, Y⁶ are each independently CR¹, CH or N, where Y⁴ or Y⁶, in the case that m = 0, may additionally be NR¹, S or 0;

   Z¹, Z², Z³ are each independently CR¹, CH or N; where Z¹, Z² or Z³, in the case that n = 0, may additionally be NR¹, S or 0;

   R¹ is independently unsubstituted or substituted alkyl, unsubstituted or substituted cycloalkyl, unsubstituted or substituted heterocycloalkyl, unsubstituted or substituted aryl, unsubstituted or substituted heteroaryl, unsubstituted or substituted alkenyl, unsubstituted or substituted cycloalkenyl, unsubstituted or substituted alkynyl, SiR² ₃, halogen, a substituent with donor or acceptor action selected from alkoxy radicals or aryloxy radicals, ester radicals, amino groups, amide radicals, CH₂F groups, CHF₂ groups, CF₃ groups, CN groups, thio groups, sulfonic acid groups, sulfonic ester groups, boronic acid groups, boronic ester groups, phosphonic acid groups, phosphonic ester groups, phosphine radicals, sulfoxide radicals, sulfonyl radicals, sulfide radicals, SR³, nitro groups, OCN, borane radicals, stannate radicals, imino groups, hydrazine radicals, hydrazone radicals, oxime radicals, nitroso groups, diazo groups, phosphine oxide groups, hydroxyl groups or SCN groups, in addition, two R¹ radicals together may form an alkylene or arylene bridge;

   R² is independently unsubstituted or substituted alkyl, unsubstituted or substituted aryl or unsubstituted or substituted heteroaryl;

   m, n are each independently 0 or 1, where the Z⁴ and Y⁵ groups are absent when, respectively, n and m = 0.
2. A metal complex according to claim 1, wherein m = 1.
3. A metal complex according to claim 1 or 2, wherein n = 1.
4. A metal complex according to any one of claims 1 to 3, wherein

   X⁴, X⁵, Y⁵, Y⁶, Z¹, Z², Z³, Z⁴ are each independently CR¹, CH or N;

   Y⁴ is CR¹, CH or N; where Y⁴, in the case that m = 0, may additionally be NR¹, S or O;

   X³, Y³ are each N or C, preferably C;

   X², Y² are each N or C, preferably C.
5. A metal complex according to claim 3 or 4, wherein

   Z¹, Z², Z³, Z⁴ are each independently CR¹, CH or N, where preferably 0, 1 or 2 Z¹, Z², Z³, Z⁴ groups are each N.
6. A metal complex according to any one of claims 2 to 4, wherein

   Y⁴, Y⁵, Y⁶ are each independently CH or CR¹; and

   Y², Y³ are each C.
7. A metal complex according to any one of claims 1 to 6, wherein the metal complex has the general formula (II)

   

   in which

   M is a metal atom selected from the group consisting of transition metals of groups IB, IIB, IIIB, IVB, VB, VIB, VIIB, VIII of the Periodic Table of the Elements (CAS version), in any oxidation state possible for the particular metal atom; preferably Ir(III), Pt(II) or Os(II), more preferably Ir(III);

   J is a mono- or dianionic ligand which may be mono- or bidentate, preferably a bidentate monoanionic ligand;

   K is an uncharged, mono- or bidentate ligand which is generally not photoactive: preferred ligands K are phosphines, especially trialkylphosphines, e.g. PEt₃, PnBu₃, triarylphosphines, e.g. PPh₃; phosphonates and derivatives thereof, arsenates and derivatives thereof, phosphites, CO, nitriles, amines, dienes which can form a p-complex with M, for example 2,4-hexadiene, η⁴-cyclooctadiene and η²-cyclooctadiene (in each case 1,3 and 1,5), allyl, methallyl, cyclooctene, norbornadiene and uncharged biscarbenes,

   o is 1, 2, 3 or 4; where o is preferably 1, 2 or 3 when M = Ir(III) more preferably 2 or 3, and is 1 or 2 when M = Pt (II) or Os (IT) ;

   p is 0, 1, 2, 3 or 4; where p is preferably 0, 1, 2, 3 or 4 when M = Ir (III), more preferably 0 or 2, and is 0, 1 or 2 when M = Pt (II) and Os(II), more preferably 0 or 2 when M = Pt(II) and more preferably 0 when M = Os(II), where p is the number of bonding sites to the metal M, i.e., when p = 2, the ligands may be two monodentate ligands or one bidentate ligand;

   q is 0, 1, 2, 3 or 4; where q is preferably 0, 1 or 2 when M = Ir(III), more preferably 0; is 0 or 1 when M = Pt(II), more preferably 0, and is 2 or 3 for Os(II), more preferably 2, where q is the number of bonding sites to the metal M, i.e., when q = 2, the ligands may be two monodentate ligands or one bidentate ligand;

   where o, p and q depend on the oxidation state and coordination number of the metal atom used and on the charge of the ligands.
8. A metal complex according to claim 7, wherein the metal complex has the general formula (IIa)

   

   in which

   M is a metal atom selected from the group consisting of transition metals of groups IB, IIB, IIIB, IVB, VB, VIB, VIIB, VIII of the Periodic Table of the Elements (CAS version), in any oxidation state possible for the particular metal atom; preferably Ir(III), Pt(II), more preferably Ir(III);

   

   is a bidentate monoanionic ligand;

   o is 1, 2, 3 or 4; where o is preferably 1, 2 or 3 when M = Ir(III), more preferably 2 or 3, and is 1 or 2 when M = Pt(II);

   p' is 0, 1 or 2; where p' is preferably 0, 1 or 2 when M = Ir(III), more preferably 0 or 1, and is 0 or 1 when M = Pt(II); where p' is the number of ligands

   

   where o and p' depend on the oxidation state and coordination number of the metal atom used.
9. A metal complex according to claim 8, wherein L in the bidentate monoanionic ligand is in each case independently selected from 0, N and C; preference is given to monoanionic bidentate ligands in which both L groups are O, C or N or one L group is O and the other L group is N or C or one L group is C and the other L group is N; the bidentate monoanionic ligands are more preferably selected from the group consisting of acetylacetonate, picolinate, carbenes, arylpyridines and arylimidazoles, and derivatives of the aforementioned compounds.
10. A metal complex according to either of claims 8 and 9, in which:

    M is Ir(III) or Pt(II), preferably Ir(III);

    o is 1, 2 or 3 when M = Ir(III), preferably 2 or 3; and is 1 or 2 when M = Pt(II);

    p' is 0, 1 or 2 when M = Ir(III), preferably 0 or 1; and is 0 or 1 when M = Pt(II);

    where the sum of o + p' is 3 when M = Ir(III) and is 2 when M = Pt(II), and o is at least 1.
11. An organic light-emitting diode comprising at least one metal complex comprising at least one ligand of the general formula (I)

    

    in which the symbols are each defined as follows:

    Y⁵, Z⁴ are each independently CR¹, CH or N;

    X², X³, Y², Y³ are each independently N or C;

    Z⁴, Z⁵ are each independently CR¹, CH or N;

    Y⁴, Y⁶ are each independently CR¹, CH or N, where Y⁴ or Y⁶, in the case that m = 0, may additionally be NR¹, S or O;

    Z¹, Z², Z³ are each independently CR¹, CH or N; where Z¹, Z² or Z³, in the case that n = 0, may additionally be NR¹, S or O;

    R¹ is independently unsubstituted or substituted alkyl, unsubstituted or substituted cycloalkyl, unsubstituted or substituted heterocycloalkyl., unsubstituted or substituted aryl, unsubstituted or substituted heteroaryl, unsubstituted or substituted alkenyl, unsubstituted or substituted cycloalkenyl, unsubstituted or substituted alkynyl, SiR² ₃, halogen, a substituent with donor or acceptor action; in addition, two R¹ radicals together may form an alkylene or arylene bridge;

    R² is independently unsubstituted or substituted alkyl, unsubstituted or substituted aryl or unsubstituted or substituted heteroaryl;

    m, n are each independently 0 or 1, where the Z⁴ and Y⁵ groups are absent when, respectively, n and m = 0.
12. A light-emitting layer comprising at least one metal complex comprising at least one ligand of the general formula (I)

    

    in which the symbols are each defined as follows:

    Y⁵, Z⁴ are each independently CR¹, CH or N;

    X², X³, Y², Y³ are each independently N or C;

    X⁴, X⁵ are each independently CR¹, CH or N;

    Y⁴, Y⁶ are each independently CR¹, CH or N, where Y⁴ or Y⁶, in the case that m = 0, may additionally be NR¹, S or O;

    Z¹, Z², Z³ are each independently CR¹, CH or N; where Z¹, Z² or Z³, in the case that n = 0, may additionally be NR¹, S or O;

    R¹ is independently unsubstituted or substituted alkyl, unsubstituted or substituted cycloalkyl, unsubstituted or substituted heterocycloalkyl, unsubstituted or substituted aryl, unsubstituted or substituted heteroaryl, unsubstituted or substituted alkenyl, unsubstituted or substituted cycloalkenyl, unsubstituted or substituted alkynyl, SiR² ₃, halogen, a substituent with donor or acceptor action; in addition, two R¹ radicals together may form an alkylene or arylene bridge;

    R² is independently unsubstituted or substituted alkyl, unsubstituted or substituted aryl or unsubstituted or substituted heteroaryl;

    m, n are each independently 0 or 1, where the Z⁴ and Y⁵ groups are absent when, respectively, n and m = 0.
13. An organic light-emitting diode comprising at least one light-emitting layer according to claim 12.
14. The use of at least one metal complex comprising at least one ligand of the general formula (I)

    

    in which the symbols are each defined as follows:

    Y⁵, Z⁴ are each independently CR¹, CH or N;

    X², X³, Y², Y³ are each independently N or C;

    X⁴, X⁵ are each independently CR¹, CH or N;

    Y⁴, Y⁶, are each independently CR¹, CH or N, where Y⁴ or Y⁶, in the case that m = 0, may additionally be NR¹, S or O;

    Z¹, Z², Z³ are each independently CR¹, CH or N; where Z¹, Z² or Z³, in the case that n = 0, may additionally be NR¹, S or O;

    R¹ is independently unsubstituted or substituted alkyl, unsubstituted or substituted cycloalkyl, unsubstituted or substituted heterocycloalkyl, unsubstituted or substituted aryl, unsubstituted or substituted heteroaryl, unsubstituted or substituted alkenyl, unsubstituted or substituted cycloalkenyl, unsubstituted or substituted alkynyl, SiR² ₃, halogen, a substituent with donor or acceptor action; in addition, two R¹ radicals together may form an alkylene or arylene bridge;

    R² is independently unsubstituted or substituted alkyl, unsubstituted or substituted aryl or unsubstituted or substituted heteroaryl;

    m, n are each independently 0 or 1, where the Z⁴ and Y⁵ groups are absent when, respectively, n and m = 0,

    in organic light-emitting diodes.
15. A device selected from the group consisting of stationary visual display units such as visual display units of computers, televisions, visual display units in printers, kitchen appliances and advertising panels, illuminations, information panels and mobile visual display units such as visual display units in cellphones, laptops, digital cameras, vehicles, and destination displays on buses and trains, comprising at least one organic light-emitting diode according to claim 11 or 13.